Ford SB 289 302 351 Windsor 1965-75 Thermostat Housing Water Neck Chrome The main difference is that

The main difference is that there is an open area under the plenum chamber

ensuring that your injectors never run dry

and forged flat-top pistons matched to your bore size

Pop-Off plates are designed to release the high pressure that builds up inside of the engine to prevent damaging or cracking your supercharger components

thus reducing the transmission temperatures for optimum performance

Ford SB 289 302 351 Windsor 1965-75 Thermostat Housing Water Neck Chrome The main difference is thatThese chrome water necks from Speedmaster add a touch of class to your cooling system. They're available for a variety of applications.